The Supreme Court will soon, as early as Thursday, issue a ruling that could affect the health care of millions of Americans. In King v. Burwell, the court could choose to allow the exchanges set up under the Affordable Care Act (Obamacare, to many) to continue operating as-is, or it could end the subsidies in most states allowing many lower-income Americans to afford the insurance offered through those sites.

At issue in the case is a phrase in the law stating that the government will subsidize patients in exchanges "established by the state." In King v. Burwell, the question is whether those subsidies should then go to people participating in the exchanges in the 34 states that didn't set up their own — that is, in states where the exchanges are federally run to some degree.

There are two broad paths the Supreme court could take here, but within those, there is a lot of room for variation:

1. A ruling for Burwell

Everything stays the way it is — people keep getting their subsidies in all states, regardless of whether the government, the state, or a mix of the two, runs their exchanges.

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2. A ruling for King

Obamacare customers in states using federal exchanges would likely lose their subsidies altogether. That means an estimated 6.4 million people could lose the tax credits that help them pay for their insurance through the exchanges.

But there are other potential, more mixed outcomes where fewer people would lose their subsidies. Because there are different configurations of federal-state cooperation, residents of some states could keep their subsidies, while others lose them. For example, five states have state-run marketplaces using federal websites — it's possible that the court could decide either way on those states, as they use federal resources, even while operating their own state marketplaces.

So what could end up mattering here is the question of what a state-run exchange is. It's possible the court could define that, but it could also send it to the administration. And depending on how the administration sets the bar on what makes a state-run exchange, this path could lead to still more litigation from Obamacare opponents, challenging how the administration set that definition, explains Linda Blumberg at the Urban Institute.

More Uninsured, Higher Premiums Possible

In the 16 states (plus the District of Columbia) with state-run exchanges, nothing will change. But the effects in the other 34 states could go beyond just more expensive health care. One study from the Urban Institute estimates that 8.2 million more people would join the ranks of the uninsured in this case. Not only that, but because so many healthy individuals would exit the exchanges, premiums would go up by an estimated 35 percent for people remaining on the exchanges in the states that lose their subsidies.

Florida by far leads the pack in having the most people at risk of losing their credits. There, a staggering 1.3 million people could lose subsidized health insurance, missing out on an average subsidy of $294 per month, according to data from the Kaiser Family Foundation. In Alaska, fewer than 17,000 people could be affected, but their price tags could grow in a huge way — by $536 per month on average.